Of course, there are trim cranks and extensions with a ratchet - but not everyone always has these to hand. Good advice is expensive, especially if you just want to trim quickly. With a small sling, you can use your harness hook as a trimming aid, for example. This can be done in seconds and without knots - and at the end, the sling disappears again as if by magic.
And this is how it's done:
Try it out!
By the way: A good extension also reduces the trimming forces. HERE there's a test of 51 models.

Editor surf
Manuel Vogel, born in 1981, lives in Kiel and learned to windsurf at the age of six at his father's surf school. In 1997, he completed his training as a windsurfing instructor and worked for over 15 years as a windsurfing instructor in various centers, at Kiel University sports and in the coaching team of the “Young Guns” freestyle camps. He has been part of the surf test team since 2003. After completing his teaching degree in 2013, he followed his heart and started as editor of surf magazine for the test and riding technique sections. Since 2021, he has also been active in wingfoiling - mainly at his home spots on the Baltic Sea or in the waves of Denmark.